A transfer feeder equipped on a transfer press is provided with a pair of feed bars arranged in parallel with each other to perform three-dimensional movement by cams, levers or the like members so that a work is clamped by fingers situated at opposing positions of the feed bars so as to allow the work to be transferred between adjacent working stations in a press housing.
Since a commonly used transfer feeder is constructed such that fingers are held immovable relative to feed bars, it is impossible to change the attitude of a work depending upon the shape of a die.
Accordingly, for example, when the work is to be lifted up from the die, a lifting operation can be performed only via a straight track with the result that a lift stroke is unavoidably elongated and thereby it becomes difficult to reduce a time required for transferring the work.
If the shape of the die does not fit the attitude of a work to be clamped by the fingers, the work can not correctly be placed in the die. This means that there is existent a certain restriction with respect to dies which can be put in practical use.
To solve a problem of such inconvenience, a proposal is already disclosed, e.g., in an official gazette of Japanese Utility Model Application NO. 190,222/1975 that fingers are supported to turn relative to feed bars via their shaft portions and a mechanism for rotating the shaft portions is provided to tilt the fingers relative to the feed bars. According to this proposal, a work is correctly placed in a die by adequately tilting the fingers in consideration of the shape of the die and reduction of a lift stroke is achieved by simultaneously performing a lifting operation and a tilting operation
Specifically, such a type of conventional finger tilting apparatus includes a plate adapted to be turned in operative association with the shaft portion of a finger, an elongated hole formed in the plate and a defining pin held on a vertical plate firmly secured to a feed bar and slidably fitted in the elongated hole so that a tilt angle of the finger is defined by allowing the defining pin to come in contact with opposite end faces of the elongated hole. With this apparatus of the type including such an elongated hole, the attitude of a work can be changed once only. Thus, for example, in case where a work is clamped while the finger is tilted, a lifting operation and a tilting operation can not simultaneously be performed when the work is to be lifted up (with the exception of a case where the finger is restored to its initial angle).
Further, in case where a tilt angle of the finger is to be changed, this is achieved by selectively fitting the defining pin into one of a plurality of different elongated holes preformed in the plate. Consequently, an attitude of the work can not be changed to an angle rather other than the tilt angles defined by the elongated holes. Thus, a requirement for changing the tilt angle in response to change or modification of the specification given to the work can not be met quickly.
The present invention has been made with the foregoing background in mind and its primary object reside in providing a finger tilting apparatus for a transfer feeder which assures that a finger can be tilted by way of plural steps.
A secondary object of the present invention is to provide a finger tilting apparatus for a transfer feeder which assures that a requirement for changing a tilt angle in response to change or modification of the specification given to a work can be met quickly.